Those who seek to make food healthier by adding chia powder should avoid several recalled brands that are linked to salmonella illnesses, the Centers for Disease Control and Prevention says.

The CDC on Friday issued a warning to consumers who may use chia powder, made from ground dried chia seeds and often added to smoothies and other foods. Some of the recalled brands are Organic Traditions, Green Smoothie Girl, Navitas Naturals and Williams-Sonoma.

Twenty-one people in 12 states from New York to California have salmonella illnesses linked to the chia powder, the CDC said. Canada is also investigating illnesses related to the outbreak.

The CDC said chia powder can have a long shelf life, so people should check to see if they have the recalled products in their homes.

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